综合式净化沼气池处理生活污水的研究

城镇生活污水净化沼气池又称净化池。它将生物厌氧消化技术与好氧处理相结合，是集生物、化学、物理处理于一体的工艺装置，主要由预处理、厌氧发酵、兼氧发酵及后处理好氧过滤等四部分组成。针对我省水质变差，环境污染严重，污水、废水排放乱的情况，我们积极吸取兄弟省的经验，因地制宜进行探索和实践，根据我省地下水位高、地质承载力差等水文地质条件，研究和推广了综合式处理生活（生产）污水、废水的净化沼气池。实践证明综合式污水净化沼气池不仅技术先进，工艺流程合理，投资省，处理效果好，而且取得了显著的环保、社会和经济效益…     

某工业园区污水处理厂低负荷运行方案优化研究

某工业园区污水处理厂建成后,短期内进水量少,针对进水水质、水量不稳定、碳氮比不合理,造成总氮、总磷出水不稳定,有超标风险等问题提出了相应的解决办法;优化了运行方案,即采用一组生化池作为匀质池,优化原厌氧-缺氧-好氧(A2/O)工艺为倒置A2/O工艺,并定时开启污水处理系统控制曝气量以及其他节能措施,优化后节能降耗效果明...     

生物接触氧化协同折流滤池处理低C/N值污水研究

低C/N值污水由于有机碳源的不足,导致传统生物脱氮过程中反硝化效果较差,氮素污染物浓度较高而难以达标排放。针对此问题,构建了生物接触氧化(BCO)协同折流滤池(BF)系统,用于处理低C/N值污水,考察了启动和运行过程中系统对污水中氮的脱除特征。研究结果表明：BCO池运行11天后可成功实现部分亚硝化,为BF池提供所需的进水水质;BF池在运行16天后可成功启动厌氧氨氧化,出水NH₄⁺-N、NO₂^--N、TN浓度均处于较低水平,TN平均去除率超过90%;BCO协同BF系统主要通过部分亚硝化、厌氧氨氧化、反硝化等多种途径共同来实现污水的高效脱氮。研究结果可为低C/N值污水的处理提供方法借鉴,同时也为预防水体富营养化提供更多的技术策略。     

MBR工艺在含油废水处理中的应用

膜生物反应器(Membrane Bio-Reactor,简称MBR)处理工艺是在真空泵和产水泵的抽吸作用下,利用膜箱上的中空纤维,对生化池的悬浮混合液进行固液分离;利用膜的选择透过性产水,在生化池中实现生物富集,生物处理效率大幅提高。截留的活性污泥以300%～400%的回流比回流至生化缺氧池,膜箱内设有曝气装置,既能对膜进行气水振荡清洗,保持膜表面清洁,又能继续在该段提供好氧微生物降解所需的氧气。该工艺具有高效的固液分离作用,出水中悬浮物等固体杂质含量很低;反应器污泥浓度高、容积负荷高,系统产泥量少;反应器内生物种群丰富,污染物去除效率高;系统采用模块化设计,占地面积小,操作简单,易于扩展,可实现全程的自动化控制。以MBR与A/O(缺氧/好氧)组合工艺为对象,研究其运行特性及维护要点。应用结果表明,在工艺控制平稳情况下,MBR处理效果明显优于A/O工艺,处理后的污水能够直接回用,或进一步深度处理后回用。     

改良A2/O+深度处理工艺在城市生活污水处理中应用案例

某污水处理厂设计规模为1万m³/d,针对传统A²/O存在的缺点,采用改良A²/O处理工艺,在A/O脱氮工艺曝气池末端增设了一个缺氧段和一个好氧段,前端增加一个厌氧段,使之在高效脱氮的同时,除磷效果与A²/O工艺相当。深度处理采用高效澄清池和深床滤池,出水水质达到《地表水环境质量标准》(GB3838-2002)V类标准。单位经营成本为1.32元/t。     

山东某县旧城区生活污水一级A达标处理工艺设计

根据山东某县污水治理总体规划及旧城区生活污水水质特点和设计出水水质达《城镇污水处理厂污染物排放标准》(GB18918-2002)一级A标准的要求,选用A/A/O工艺+絮凝+转盘过滤+消毒为主体的处理工艺对该县生活污水进行处理。该项目处理方式采用分散式处理,处理后水质达标,出水可作为生产生活用水回用,实现了污水综合利用和零排放,并为满足一级A排放标准条件下小城镇生活污水处理积累了设计经验。     

某生活污水处理陶瓷平板膜MBR工艺实验研究

通过陶瓷平板膜MBR工艺对生活污水进行处理,在来水COD在204.5～269.16mg/L,氨氮在21.95～36.24mg/L,总氮在41.4～52.99mg/L,总磷在4.05～5.41mg/L的情况下,考察膜通量和出水满足一级A排放标准相关设计参数。出水通量逐渐增大至26L/m²·h,跨膜压差逐渐增大。在好氧池停留时间6.5h,缺氧池停留时间2h情况下,出水COD、氨氮、总氮基本能够稳定在一级A范围内,污泥负荷为：0.076kgBOD/(kgMLVSS·d),反硝化速率为0.038 kgNO₃-N/(kgMLSS·d),出水总磷难以达标,需要辅助化学除磷。     

A/O生物滤池处理生活污水的挂膜启动试验研究

本试验中,A/O生物滤池挂膜启动分为两个阶段进行:第一阶段,好氧柱利用活性污泥接种后循环曝气培养生物膜;第二阶段,缺氧柱通入待处理的水及从挂膜完成后好氧柱回流的水,并逐步提高滤速启动,进行缺氧微生物的培养和驯化。本试验二级好氧滤柱采用沈阳北部污水处理厂回流污泥接种,以待处理的原水启动挂膜。试验结果表明,当滤速8.8L/h(2m/h)小流量进水,回流比1:1,二级好氧柱曝气量25L/h时,在25天内,能在填料表面形成较稳定的生物膜,出水COD、NH3-N及浊度能分别稳定到12mg/L、5.22mg/L及10NTU以下。     

A/A/O生物脱氮处理焦化污水工艺介绍

萍钢焦化厂新建酚、氰废水处理站采用了先进的A/A/O法生物脱氮工艺,此工艺将污水二级处理中的缺氧、好氧两大类方法有机结合在一起,对焦化废水中的酚、氰、COD、氨氮等多种污染物均有较高的去除率,尤其是出水氨氮含量远远低于钢铁行业一级排放标准(15mg/l).文章详细介绍了A/A/O生物脱氮的原理、运行控制和工艺流程.     

改良工艺污水处理厂不停产提标扩充工程案例分析

改进的A2/O深度处理技术脱氮除磷效果稳定高效,耐冲击承载能力强,维护简单,结构简单,适合北方寒冷地区的大型城市污水处理厂.通过A2/O工艺的改良厌氧、缺氧、好氧三种不同的环境条件和各种微生物菌群的有机配比,可以同时去除有机物、氮和磷.深度处理工艺(高级工艺)通过凝聚、沉淀、过滤、消毒进一步去除BOD5、CODCr、SS、TP.本文以某区生活污水处理站为例,对不停产改良A2/O工艺模式进行论证研究.     

Potential improvement to a citric wastewater treatment plant using bio-hydrogen and a hybrid energy system

Treatment of highly concentrated organic wastewater is characterized as cost-consuming. The conventional technology uses the anaerobic-anoxic-oxic process (A²/O), which does not produce hydrogen. There is potential for energy saving using hydrogen utilization associated with wastewater treatment because hydrogen can be produced from organic wastewater using anaerobic fermentation. A 50 m³ pilot bio-reactor for hydrogen production was constructed in Shandong Province, China in 2006 but to date the hydrogen produced has not been utilized. In this work, a technical-economic model based on hydrogen utilization is presented and analyzed to estimate the potential improvement to a citric wastewater plant. The model assesses the size, capital cost, annual cost, system efficiency and electricity cost under different configurations. In a stand-alone situation, the power production from hydrogen is not sufficient for the required load, thus a photovoltaic array (PV) is employed as the power supply. The simulated results show that the combination of solar and bio-hydrogen has a much higher cost compared with the A²/O process. When the grid is connected, the system cost achieved is 0.238 US$ t⁻¹ wastewater, which is lower than 0.257 US$ t⁻¹ by the A²/O process. The results reveal that a simulated improvement by using bio-hydrogen and a FC system is effective and feasible for the citric wastewater plant, even when compared to the current cost of the A²/O process. In addition, lead acid and vanadium flow batteries were compared for energy storage service. The results show that a vanadium battery has lower cost and higher efficiency due to its long lifespan and energy efficiency. Additionally, the cost distribution of components shows that the PV dominates the cost in the stand-alone situation, while the bio-reactor is the main cost component in the parallel grid.     

Electrical energy production and operational strategies from a farm-scale anaerobic batch reactor loaded with rice straw and piggery wastewater

A farm-scale biogas plant loaded with untreated rice straw and co-digested with raw pig wastewater was operated and monitored during a complete digestion cycle. One active anaerobic digester cell (6600 m³) containing 727 tons of rice straw, 285 tons of pig wastewater and approximately 1300 tons of water was operated for a total of 422 days. Cumulative energy production of 295 MWh and an estimated specific methane yield of 181 LCH₄/kgVS added was achieved. A direct correlation between daily power production and digester temperature was observed, with a maximum power production of 2.74 MWh/d. Mesophilic conditions were reached inside the digester during the summer months by recovering waste heat from the engine and recycling it through the leachate recirculation process.A slow start-up period of approximately 200 days was observed, but increased leachate recirculation rates (from 0.04 to >0.14 m³/m³straw-d) resulted in increased gas production that initiated the microbial growth phase in the digestion cycle. Although sufficient buffering capacity as well as macro- and micronutrients were supplied to the system by the pig wastewater, an overall straw (dry wt.) to wastewater ratio (wet wt.) of 1 to 1.4 is recommended to improve gas production and decrease the acclimation period. A raw economic assessment of the system shows an investment recovery time of 8.3 years. Improvements such as continuous leachate recirculation, a more efficient heat exchange system to maintain mesophilic conditions year round, and periodic addition of fresh wastewater and sludge acclimated to lignocellulosic material are recommended to achieve a more sustainable and profitable system.     

ADM1 modeling of UASB treating domestic wastewater in Nepal

The Anaerobic Digestion Model 1 (ADM1) was applied to the anaerobic digestion process in an Upflow Anaerobic Sludge Blanket (UASB) reactor treating domestic wastewater. It was evaluated based on data from a 250 L pilot scale reactor. The wastewater influent degradable characteristics and Sludge Retention Time (SRT) were established by several trial and errors simulation to establish appropriate values for parameters not measured experimentally. The model was further verified against varying load experimental results to ensure its usefulness for a wide range of relevant loads. The best fit was obtained using 60 d SRT and parameters recommended for mesophilic conditions, with average experimental values within 10% of the simulated results. The model gave a good estimation of reality and could be applied for feasibility analysis, design and operation of full-scale small plants to be used in rural areas. Kathmandu University (KU) domestic wastewater treatment plant simulation was used as example of such. It showed that a reactor volume of about 4 m³ (6 h HRT) would give reasonable reactor performance with 1.7 m³/d biogas production.     

Novel design of a multitube microbial fuel cell (UM2FC) for energy recovery and treatment of membrane concentrates

A two-stage treatment process, consisting of a flat sheet membrane system and a novel upflow multitube microbial fuel cell (UM²FC), was investigated to simultaneously treat concentrate streams—as well as produce electricity. This study tested the treatment of the retained part (i.e membrane concentrate) of the membrane process and electricity production using an air-cathode UM²FC inoculated with sediment sample collected from Golden Horn, Istanbul. The electrochemical behaviors were investigated using electrochemical methods to identify how membrane concentrates effects the reactor performance. The treatment of domestic wastewater was performed using a lab-scale cross-flow filtration apparatus with a UH050 membrane and the chemical oxygen demand (COD) removal efficiency as a result of membrane treatment was 87%. Then the UM²FC was fed sequentially from the feed tank when desired retained ratios (25% and 50%) observed. The maximum power density obtained was 25.138 mW m⁻² in the 50% concentrate or a volume concentration ratio (VCR) of 2 fed UM²FC which was 244% higher than that achieved using raw wastewater (7.303 mW m⁻²) and COD removal was >65% in UM²FC. The contribution of different resistances such as ohmic, charge transfer and mass transfer resistances of the reactor under different stages was ascertained through the measurements using electrochemical impedance spectroscopy (EIS) and the results showed that an increasing organic loading reduced the internal resistance and enhanced power. On the whole, study reported new findings such as a new treatment technology for membrane concentrate treatment and gives insight to literature on reactor design.     

Evaluation of low cost cathode materials for treatment of industrial and food processing wastewater using microbial electrolysis cells

Microbial electrolysis cells (MECs) can be used to treat wastewater and produce hydrogen gas, but low cost cathode catalysts are needed to make this approach economical. Molybdenum disulfide (MoS₂) and stainless steel (SS) were evaluated as alternative cathode catalysts to platinum (Pt) in terms of treatment efficiency and energy recovery using actual wastewaters. Two different types of wastewaters were examined, a methanol-rich industrial (IN) wastewater and a food processing (FP) wastewater. The use of the MoS₂ catalyst generally resulted in better performance than the SS cathodes for both wastewaters, although the use of the Pt catalyst provided the best performance in terms of biogas production, current density, and TCOD removal. Overall, the wastewater composition was more of a factor than catalyst type for accomplishing overall treatment. The IN wastewater had higher biogas production rates (0.8–1.8 m³/m³-d), and COD removal rates (1.8–2.8 kg-COD/m³-d) than the FP wastewater. The overall energy recoveries were positive for the IN wastewater (3.1–3.8 kWh/kg-COD removed), while the FP wastewater required a net energy input of −0.7–−1.2 kWh/kg-COD using MoS₂ or Pt cathodes, and −3.1 kWh/kg-COD with SS. These results suggest that MoS₂ is the most suitable alternative to Pt as a cathode catalyst for wastewater treatment using MECs, but that net energy recovery will be highly dependent on the specific wastewater.     

Performance of Square and Trapezoidal photoreactors for solar hydrogen recovery from various industrial sulphide wastewater using CNT/Ce3+ doped TiO2

CNT/Ce³⁺ doped TiO₂ powder was synthesized using a sol-gel method and characterized by X-ray Diffraction, UV–vis Diffuse Reflectance Spectroscopy, FTIR, EDX, Raman, Transmission Electron Microscopy (TEM), BET and PL. Direct sunlight illumination was used to check the photocatalytic activity of CNT/Ce³⁺ doped TiO₂ for hydrogen production from sulphide wastewater. Sulphide wastewater collected from various industries viz., STP (Sewage Treatment Plant), Refinery (Amine solution) and Tannery (soak pit) were used to test the photocatalytic hydrogen recovery. The suitable industrial wastewater which generates maximum hydrogen was used to check the effect of various operating parameters viz., sulphide ion concentrations, sulphite ion concentrations and catalyst dosage. The maximum hydrogen recovery achieved was found to be 14,500 μmol/h.     

Urban lignocellulosic biomass can significantly contribute to energy production in municipal wastewater treatment plants – A GIS-based approach for a metropolitan area

The common fermentation of biogenic wastes and sewage sludge in digesters of municipal wastewater treatment plants is a technically feasible and economically viable approach. As the number of rural biogas production sites is steadily increasing, the question has been raised which biomass feedstocks are left available in sufficient quantities to be used for energy generation at wastewater treatment plant level. The contribution of lignocellulosic biomass collected from urban areas is generally neglected within this context. In the present study, 24 urban substrates have been analyzed for their theoretical methane potential, while 13 of them were tested in batch assays for the determination of their practical achievable methane yield. The theoretical evaluation of the methane potential yielded values ranging between 0.393 and 0.576 Nm³ kgVS⁻¹. The methane yields obtained by batch assays showed significantly lower yields, which depends on the individual composition of the substrates in terms of lignin, hemicellulose and cellulose. A GIS spatial analysis for the Rhine-Ruhr metropolitan area was performed to evaluate the feasible capacity of urban biomass as co-fermentation feedstock in digesters of municipal wastewater treatment plants. The analysis revealed that green urban areas provide a significant quantity of biomass of 377 t_FM d⁻¹ that could cover 67% of the annual energy demand of twelve typical wastewater treatment plants located in the metropolis.     

Effluents with soluble metabolites generated from acidogenic and methanogenic processes as substrate for additional hydrogen production through photo-biological process

The feasibility of utilizing effluents generated from acidogenic [producing biohydrogen (H₂)] and methanogenic [producing methane] processes was studied for additional H₂ production by terminally integrating with photo-biological process employing enriched mixed culture. Experimental data has depicted enhanced process efficiency with respect to additional H₂ production and substrate degradation through photo-biological process. However, the efficiency was found to depend on the process used in the first stage along with nature and composition of the substrate. Acidogenic process in the first stage had more positive influence on photo-biological H₂ production [synthetic wastewater – 14.40 mol/Kg COD_R and 15.16 mol/Kg COD_R (with vitamins); dairy wastewater – 13.29 mol/Kg COD_R and 13.70 mol/Kg COD_R (with vitamins)] over the corresponding methanogenic process. Effluent generated from acidogenic treatment of dairy wastewater yielded high substrate degradation rate (SDR) [1.20 Kg COD/m³ day and 1.34 Kg COD/m³ day (vitamins)] followed by synthetic wastewater [0.92 Kg COD/m³ day and 1.05 Kg COD/m³ day (vitamins)]. Among the studied experimental variations chemical wastewater evidenced poor H₂ production and SDR. Vitamin solution showed positive influence on both H₂ production and wastewater treatment irrespective of the experimental variations studied.     

A monetary comparison of energy recovered from microbial fuel cells and microbial electrolysis cells fed winery or domestic wastewaters

Microbial fuel (MFCs) and electrolysis cells (MECs) can be used to recover energy directly as electricity or hydrogen from organic matter. Organic removal efficiencies and values of the different energy products were compared for MFCs and MECs fed winery or domestic wastewater. TCOD removal (%) and energy recoveries (kWh/kg-COD) were higher for MFCs than MECs with both wastewaters. At a cost of $4.51/kg-H₂ for winery wastewater and $3.01/kg-H₂ for domestic wastewater, the hydrogen produced using MECs cost less than the estimated merchant value of hydrogen ($6/kg-H₂). 16S rRNA clone libraries indicated the predominance of Geobacter species in anodic microbial communities in MECs for both wastewaters, suggesting low current densities were the result of substrate limitations. The results of this study show that energy recovery and organic removal from wastewater are more effective with MFCs than MECs, but that hydrogen production from wastewater fed MECs can be cost effective.     

Biohydrogen production from purified terephthalic acid (PTA) processing wastewater by anaerobic fermentation using mixed microbial communities

Purified terephthalic acid (PTA) processing wastewater was evaluated as a fermentable substrate for hydrogen (H₂) production with simultaneous wastewater treatment by dark-fermentation process in a continuous stirred-tank reactor (CSTR) with selectively enriched acidogenic mixed consortia under continuous flow condition in this paper. The inoculated sludge used in the reactor was excess sludge taken from a second settling tank in a local wastewater treatment plant. Under the conditions of the inoculants not less than 6.3 gVSS/L, the organic loading rate (OLR) of 16 kgCOD/m³ d, hydraulic retention time (HRT) of 6 h and temperature of (35 ± 1) °C, when the pH value, alkalinity and oxidation–reduction potential (ORP) of the effluent ranged from 4.2 to 4.4, 280 to 350 mg CaCO₃/L, and −220 to −250 mV respectively, soluble metabolites were predominated by acetate and ethanol, with smaller quantities of propionate, butyrate and valerate. Stable ethanol-type fermentation was formed with the sum of ethanol and acetate concentration ratio of 70.31% to the total liquid products after 25 days operation. The H₂ volume content was estimated to be 48–53% of the total biogas and the biogas was free of methane throughout the study. The average biomass concentration was estimated to be 10.82 gVSS/L, which favored H₂ production efficiently. The rate of chemical oxygen demand (COD) removal reached at about 45% and a specific H₂ production rate achieved 0.073 L/gMLVSS d in the study. This CSTR system showed a promising high-efficient bioprocess for H₂ production from high-strength chemical wastewater.